I have about 2" of bedding. Pothos is good, bromiliads are good as long as you realize that once the flower dies the bromiliad is done and you have to break off the "pup" that will grow off the side and plant that and then wait **years** for it to bloom again. The book "Crested Geckos" by Adam Black has a bit about native New Caledonian plants (p.45). One that he recommends is a split-leafed plant "Epipremnum pinnatum" that I have in my crestie viv. It provides excellent coverage. To help it climb I got one of those fake vines, twisted it around in the cage and let the plant climb up it.
Aliza